ADU Regulations in Gresham, Oregon
Updated September 29, 2026
Multnomah County's second-largest city, Gresham permits ADUs by right under Oregon's HB 2001. The city actively encourages ADU construction through reduced System Development Charges (SDCs), making it an affordable option for property owners.
Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Gresham as of 2026. Regulations are governed by Oregon's HB 2001 (2019) which requires ADU approval by-right in all residential zones statewide.
| Regulation | Requirement |
|---|---|
| Maximum Size | 1,200 sq ft |
| Property Setbacks | 5 ft rear, 5 ft side |
| Extra Parking Required | Not required |
| Owner Occupancy | Not required |
Additional Local Requirements for Gresham
- ADU by right in all residential zones
- Minimum 200 sq ft
- Max height: 20 ft
- System development charges may be reduced for ADUs
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Can I build an ADU in Gresham?
Gresham permits ADUs under Oregon law. The city offers SDC reductions for ADUs to encourage construction.
What is the maximum ADU size allowed in Gresham?
ADUs in Gresham can be up to 1,200 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Gresham planning department before designing your project.
What are the setback requirements for an ADU in Gresham?
ADUs in Gresham generally require setbacks of 5 ft rear, 5 ft side. Oregon's HB 2001 (2019) requires cities to allow ADUs in residential zones, but the exact setback figures come from Gresham's own code — confirm them with the city before you design.
Disclaimer: This guide summarises publicly available city zoning rules and is for general information only — it is not legal or architectural advice. Codes change; always confirm current requirements with the Gresham planning department before you design or build.